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Calculate allocation shares for livestock commodities

Source: R/core_model_allocation.R
calc_allocation_shares.Rd

Calculates biophysical allocation shares for commodities (meat, milk, fibre, work, eggs) based on their total energy requirements.

Usage

calc_allocation_shares(
  species_short,
  meat_allocation_energy,
  milk_allocation_energy,
  fibre_allocation_energy,
  work_allocation_energy,
  egg_allocation_energy
)

Arguments

species_short

Character. Code identifying the livestock species. Supported values include:

  • PGS: pigs

  • CML: camels

  • CTL: cattle

  • BFL: buffalo

  • SHP: sheep

  • GTS: goats

meat_allocation_energy

Numeric. Energy required by a given sex–age cohort for total meat output by cohort during the assessment period, equal to the energy needed to produce all live-weight gain to reach the target slaughter weight (MJ/cohort/assessment period).

milk_allocation_energy

Numeric. Energy required to produce total milk output by cohort (MJ/cohort/assessment period). Non-zero values are applicable only to milk-producing species and cohorts (species=CTL, BFL, CML, SHP, GTS; cohorts=FA). All other species–cohort combinations are assigned a value of 0.

fibre_allocation_energy

Numeric. Energy required to produce all fibre output by cohort (MJ/cohort/assessment period).

work_allocation_energy

Numeric vector. Energy required to provide all draught power (traction/work) by cohort (MJ/cohort/assessment period).

egg_allocation_energy

Numeric vector. Energy required to produce all eggs during the assessment period (MJ/cohort/assessment period).

Value

A named list of numeric vectors with same length as input, containing:

meat_share_allocation

Numeric. Allocation share assigned to meat (fraction).

milk_share_allocation

Numeric. Allocation share assigned to milk (fraction).

fibre_share_allocation

Numeric. Allocation share assigned to fibre (fraction).

work_share_allocation

Numeric. Allocation share assigned to work (fraction).

eggs_share_allocation

Numeric. Allocation share assigned to eggs (fraction).

Details

These fractions represent the proportions of total environmental burdens (e.g., GHG emissions) that will be allocated to each commodity in subsequent steps of the assessment.

This function is part of the run_allocation_module() of the Global Livestock Environmental Assessment Model (GLEAM), which incorporates a biophysical allocation approach, aligned with the IDF Global Carbon Footprint Standard for the Dairy Sector (IDF, 2022), and adapted from Thoma and Nemecek (2020), and is consistent with FAO LEAP livestock LCA guidelines (FAO, 2016a, 2016b, 2016c). This approach also aligns with ISO 14044:2006 (Section 4.3.4.2, Step 2) by using underlying physical (energy-based) relationships to assign shared inputs and outputs in multifunctional livestock production systems.

In accordance with ISO 14044:2006 (Section 4.3.4.2, Step 2), known processing or biophysical relationships may be used to assign shared inputs and outputs of a single production unit to individual products or sub-units. In livestock systems, this includes apportioning shared feed and energy use according to physiological energy requirements (e.g., net energy for lactation, growth..etc.). If the resulting process remains multifunctional, these energy terms may subsequently be used to derive allocation factors among co-products.

This function calculates biophysical allocation fractions for commodities (meat, milk, fibre, work, eggs) for all species. The allocation is based on commodity-specific energy requirements calculated using calc_meat_allocation_energy, calc_milk_allocation_energy, calc_fibre_allocation_energy, calc_work_allocation_energy, and calc_eggs_allocation_energy.

Pig species (PGS): allocation is not based on energy partitioning because pig production is treated as functionally single-output (edible meat). Consequently, 100% of the allocation is assigned to the meat commodity (meat share = 1; all other commodity shares = 0), independent of the energy inputs.

This function is part of the run_allocation_module().

References

ISO. (2006). Environmental management — Life cycle assessment — Requirements and guidelines (ISO 14044:2006). International Organization for Standardization, Geneva.

IDF. (2022). The IDF Global Carbon Footprint Standard for the Dairy Sector. Bulletin of the IDF No. 520/2022. International Dairy Federation, Brussels.

Thoma, G., and Nemecek, T. (2020). Allocation between milk and meat in dairy LCA: Critical discussion of the IDF’s standard methodology. In Proceedings of the 12th International Conference on Life Cycle Assessment of Food (LCAFood 2020) (pp. 83–89), 13–16 October, Berlin, Germany.

FAO. (2016a). Environmental performance of large ruminant supply chains: Guidelines for assessment. Livestock Environmental Assessment and Performance (LEAP) Partnership. FAO, Rome, Italy.

FAO. (2016b). Greenhouse gas emissions and fossil energy use from small ruminant supply chains: Guidelines for assessment. Livestock Environmental Assessment and Performance (LEAP) Partnership. FAO, Rome, Italy.

FAO. (2016c). Greenhouse gas emissions and fossil energy use from poultry supply chains: Guidelines for assessment. Livestock Environmental Assessment and Performance (LEAP) Partnership. FAO, Rome, Italy.

See also

run_allocation_module, calc_meat_allocation_energy, calc_milk_allocation_energy, calc_fibre_allocation_energy, calc_work_allocation_energy, calc_eggs_allocation_energy